Adjustable interbody fusion device and method of use

ABSTRACT

Interbody fusion devices, interbody fusion device systems, insertion tools, methods for assembling an interbody fusion device, and methods a method for inserting a medical device between two vertebral bodies are disclosed. The interbody fusion device includes a body member with a pivot cylinder, a superior member with a pivot channel that is configured to engage the pivot cylinder, and a movement mechanism for moving the superior member relative to the body member. The interbody fusion device systems may include an interbody fusion device and an insertion tool. Also disclosed is a method of assembling an interbody fusion device. In addition, a method for inserting a medical device between two vertebral bodies in a spine is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/985,301 filed on May 21, 2018, which will issue as U.S. Pat. No.10,667,925 on Jun. 2, 2020, which is a continuation of U.S. applicationSer. No. 14/763,311 filed Jul. 24, 2015, which issued as U.S. Pat. No.9,974,664 on May 22, 2018, which is a U.S. National Stage Filing under35 U.S.C. § 371 from International Application No. PCT/US2014/012848filed on Jan. 24, 2014, and published as WO 2014/116891 on Jul. 31,2014, which claims priority benefit under 35 U.S.C. § 119(e) of U.S.provisional application No. 61/756,048 filed Jan. 24, 2013, which allapplications are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates generally to general surgery, orthopaedicand neurosurgical implants used for insertion within a space betweenhard tissue structures, and more specifically, but not exclusively,concerns devices implanted between bones to replace resected, fracturedor diseased structures and to maintain or reestablish proper spacingbetween two bones.

BACKGROUND OF THE INVENTION

Damage or disease that affects the integral structure of a bone or otherstructures, may lead to neurologic impairment or loss of structuralsupport integrity with possible permanent damage to the surrounding softtissue and adjacent neurologic, vascular and systemic structures.Maintaining or reestablishing anatomic spacing within a bone structureor other structural tissue is critical to ensuring continuedfunctionality and mobility of the patient and avoidance of long-termserious neurological, vascular or other systemic impairments. Pleasenote that the terms “implant” and “device” may be used interchangeablyand have the same meaning herein.

SUMMARY OF THE INVENTION

Advancement of the state of interbody fusion devices and implants andthe surgical management relating to the clinical presentation of damagedtissue structures within the body is believed desirable. Exampleembodiments of the invention that satisfies the need for improvements toan expandable interbody fusion device used to treat patients sufferingfrom either diseased or damaged disc or other tissue structures includesa superior member coupled to a body member.

The present invention provides in one aspect, an interbody fusion devicehaving a body member including a pivot cylinder, a superior memberincluding a pivot channel, and a movement mechanism for moving thesuperior member relative to the body member. The pivot cylinder beingconfigured to engage the pivot channel.

The present invention provides in another aspect, an interbody fusiondevice system. The system including an interbody fusion device and aninsertion tool. The interbody fusion device may include a base memberwith a pivot cylinder, a top member with a hinge channel, and anexpansion mechanism for moving the top member relative to the basemember. The pivot cylinder may be configured to engage the hingechannel. The insertion tool may include a handle, an insertion end, atleast one tube extending away from the handle and connecting the handleand the insertion end. The tool may also include a first knob configuredto couple to the handle. The tool may further include an actuation barmoveable between a first and second position to enable the first knob toengage an adjustment mechanism in the first position and a securementmechanism in the second position.

The present invention also provides in another aspect, a method forassembling an interbody fusion device, including obtaining a bottommember, an expansion mechanism, and a top member. The method may alsoinclude inserting the expansion mechanism into the bottom member andsecuring a first portion of the expansion mechanism in the bottommember. In addition, the method may include coupling the top member tothe bottom member. The method may further include aligning the topmember with the bottom member and a second portion of the expansionmechanism.

The present invention provides in yet another aspect, a method forinserting a medical device between two vertebral bodies in a spine. Themethod may include obtaining a medical device. The medical device mayinclude a base member, a top member configured to be coupled to the basemember, and a movement mechanism engaging the top member and the basemember. The method may also include inserting and coupling a tool intoat least two openings within the medical device. The method may furtherinclude slidingly inserting the medical device into a space between twovertebral bodies. The method may also include rotating a knob of thetool to move a first end of the top member in a vertical directionrelative to the base member.

Further, additional features and advantages are realized through thetechniques of the present invention. Other embodiments and aspects ofthe invention are described in detail herein and are considered a partof the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. It is emphasized that, in accordance with thestandard practice in the industry, various features are not drawn toscale. In fact, the dimensions of the various features may bearbitrarily increased or reduced for clarity of discussion. Theforegoing and other objects, features and advantages of the inventionare apparent from the following detailed description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a posterior perspective view of one embodiment of anexpandable interbody fusion device, in accordance with an aspect of thepresent invention;

FIG. 2 is an isometric view of the expandable interbody fusion device ofFIG. 1 with the moveable member extended, in accordance with an aspectof the present invention;

FIG. 3 is a side view of the expandable interbody fusion device of FIG.1 with a moveable member extended, in accordance with an aspect of thepresent invention;

FIG. 4 is an exploded view of the expandable interbody fusion device ofFIG. 1 , in accordance with an aspect of the present invention;

FIG. 5 is a superior perspective view of the expandable interbody fusiondevice of FIG. 1 , showing only the base or bottom member, in accordancewith an aspect of the present invention;

FIG. 6 is an inferior perspective view of the expandable interbodyfusion device of FIG. 1 , showing only the top or superior member, inaccordance with an aspect of the present invention;

FIG. 7 is a posterior elevational view of the expandable interbodyfusion device of FIG. 1 without the top member, showing the expansionassembly extended and tilted to accommodate the slanted top member, inaccordance with an aspect of the present invention;

FIG. 8 is an exploded view of the expansion mechanism of the expandableinterbody fusion device of FIG. 1 , in accordance with an aspect of thepresent invention;

FIG. 9 is an isometric view of another expandable interbody fusiondevice with a transparent base member showing a drive rod and lockingmechanism, in accordance with an aspect of the present invention;

FIG. 10 is a partially exploded isometric view of the expandableinterbody fusion device of FIG. 9 showing the locking mechanism beinginserted into the interbody fusion device, in accordance with an aspectof the present invention;

FIG. 11 is an isometric view of the locking mechanism of FIGS. 9 and 10, in accordance with an aspect of the present invention;

FIG. 12 is a perspective view of the expandable interbody fusion deviceof FIG. 1 and an expansion tool, in accordance with an aspect of thepresent invention;

FIG. 13 is a top perspective view of the expansion tool of FIG. 12 , inaccordance with an aspect of the present invention;

FIG. 14 is a truncated anterior view of the attachment end of theexpansion tool of FIG. 12 , in accordance with an aspect of the presentinvention;

FIG. 15 is a perspective view of the expansion tool of FIG. 13 with atransparent outer housing and the knob in a first position, inaccordance with an aspect of the present invention;

FIG. 16 is a truncated distal view of the handle end of the expansiontool of FIG. 15 , in accordance with an aspect of the present invention;

FIG. 17 is a perspective view of the expansion tool of FIG. 13 with atransparent outer housing and the knob in a second position, inaccordance with an aspect of the present invention;

FIG. 18 is truncated distal view of the handle end of the expansion toolof FIG. 17 , in accordance with an aspect of the present invention;

FIG. 19 is an exploded view of the tool of FIG. 13 , in accordance withan aspect of the present invention;

FIG. 20 is a perspective view of the expandable interbody fusion deviceof FIG. 1 and another embodiment tool, in accordance with an aspect ofthe present invention;

FIG. 21 is a perspective view of the tool of FIG. 20 with a transparentouter housing and intermediate housing, in accordance with an aspect ofthe present invention;

FIG. 22 is an exploded view of the tool of FIG. 20 , in accordance withan aspect of the present invention;

FIG. 23 is an exploded view of the handle portion of the tool of FIG. 20, in accordance with an aspect of the present invention;

FIG. 24 is a truncated view of the adjustment end of the adjustmentmechanism of the tool of FIG. 20 , in accordance with an aspect of thepresent invention;

FIG. 25 is a perspective view of the locking mechanism inserter of thetool of FIG. 20 , in accordance with an aspect of the present invention;

FIG. 26 is a truncated view of the locking mechanism inserter of thetool of FIG. 20 and the locking mechanism of FIG. 11 , in accordancewith an aspect of the present invention;

FIG. 27 is a truncated view of the tool of FIG. 20 with the lockingmechanism inserter inserted into the implant of FIG. 1 , in accordancewith an aspect of the present invention;

FIG. 28 is a perspective view of an implant with the locking mechanismof FIG. 11 inserted into the base member, in accordance with an aspectof the present invention;

FIG. 29 is a posterior perspective view of another embodiment of anexpandable interbody fusion device, in accordance with an aspect of thepresent invention;

FIG. 30 is a side view of the expandable interbody fusion device of FIG.29 with a moveable member extended, in accordance with an aspect of thepresent invention;

FIG. 31 is an exploded view of the expandable interbody fusion device ofFIG. 29 , in accordance with an aspect of the present invention;

FIG. 32 is a superior perspective view of the expandable interbodyfusion device of FIG. 29 , in accordance with an aspect of the presentinvention;

FIG. 33 is an inferior perspective view of the expandable interbodyfusion device of FIG. 29 , in accordance with an aspect of the presentinvention; and

FIG. 34 depicts an embodiment of a surgical method for maintaining aspace between two vertebral bodies in a spine.

DETAILED DESCRIPTION

Generally stated, disclosed herein is an interbody fusion device orinterbody device that typically includes a top member, a base member,and at least one expansion mechanism. Further, the interbody fusiondevice may include an extendable/retractable member or expansionassembly and an expansion tool for expansion and contraction of theinterbody device. The retractable member extending in a verticaldirection. As used herein, the terms “interbody fusion device,” “medicaldevice,” “device,” “interbody device” and “implant” may be usedinterchangeable as they essentially describe the same type of device.Further, the corresponding expansion tool may also be referred to as“tool” or “instrument” and these terms may be used interchangeably.Finally, described herein is a surgical method for using the interbodyfusion device to maintain a space between two vertebral bodies within apatient suffering from a diseased or damaged disc or spinal column.

As depicted in FIGS. 1-8 , the general arrangement of an adjustableinterbody fusion device 100, in accordance with an aspect of the presentinvention, includes a base member 110, a top member 130, and anexpansion mechanism 140. In this detailed description and the followingclaims, the words proximal, distal, anterior, posterior, medial,lateral, superior and inferior are defined by their standard usage forindicating a particular part of a bone or implant according to therelative disposition of the natural bone or directional terms ofreference. For example, “proximal” means the portion of an implantnearest the torso, while “distal” indicates the portion of the implantfarthest from the torso. As for directional terms, “anterior” is adirection towards the front side of the body, “posterior” means adirection towards the back side of the body, “medial” means towards themidline of the body, “lateral” is a direction towards the sides or awayfrom the midline of the body, “superior” means a direction above and“inferior” means a direction below another object or structure.

It is shown in FIGS. 1-3 , the example of the adjustable interbodyfusion device 100. The device 100 as seen in FIG. 1 may have, forexample, a generally rectangular geometry with various configured longsides to facilitate insertion and bone coverage. Although it would beunderstood by one skilled in the art that other outside configurationscan be used. The implant 100 may likely include at least one moveabletop or superior member 130 and a base, body, or bottom member 110. Thetop member 130 may be detachably coupled to the base member 110.

As seen in FIGS. 1 and 2 , base member 110 may have at least one throughhole or central opening 102 for insertion of bone graft materialdisposed on the inferior and superior bone contacting surfaces 104. Theopening 102 typically extends through both bone contacting surfaces 104of the base and top members 110, 130 and into the inner cavity of theassembled device 100. The size and configuration of the opening 102allow the surgeon to place bone graft material inside the implant 100 toachieve a continuous fusion between the inferior and superior vertebralbodies.

As shown in FIG. 1 , the superior and inferior bone contacting surfaces104 may be generally parallel to each other. However, the expansionmechanism or movement mechanism 140 (these names may be usedinterchangeably), (see FIG. 8 ), will allow the user to angle one end ofthe bone contacting surface 104 of the top member 130 relative to thebone contacting surface 104 of the base member 110 as seen in FIGS. 2and 3 , wherein the far end is fully expanded and the near end remainsretracted. FIGS. 1-4 show the bone contacting surfaces 104 to haveteeth-like or tine structures projecting away from the superior andinferior surfaces. One skilled in the art would recognize that othersurface treatments may be applied to the bone contacting surfaces 104 toenhance fixation with the opposing bone surface. Although not shown, itis understood by one skilled in the art that modular bone contactingsurfaces, caps or plates may be used to provide for varying types ofbone contacting surfaces and structures, including, but not limited tosharp tines, porous coatings, biomaterial or ingrowth surfaces, andridge structures. It is also understood that the bone contactingsurfaces 104 may be coated with nano-surfacing, bioactive or bone/tissueingrowth coatings.

As seen in FIGS. 4 and 5 , the base member 110 may also include a toolalignment channel 112 extending along a side of the base member 110 fromthe posterior end, a tool attachment opening 114 on the posterior end ofthe base member 110, and an adjustment opening 116 on the posterior endof the base member 110 and which may be opposite the tool alignmentchannel 112, as seen in FIGS. 1 and 2 . The base member 110 may alsoinclude a hole or lumen 118 near the proximal end of the base member 110to house an expansion mechanism 140 (see FIG. 8 ), which will bediscussed in greater detail below. The hole 118 may have a smoothvertical wall to facilitate insertion and unrestricted rotation of acylindrical gear 150 of the expansion mechanism 140 (see FIG. 8 ). Thehole 118 of the base member 110 may also include an internalcircumferential shoulder 120 and a notch 121. In addition, the basemember 110 may include a channel 122 extending from the adjustmentopening 116 interiorly along a lateral side of the base member 110 toengage the hole 118. The base member 110 may also include a pivotcylinder 124, an alignment protrusion 126, and an opening 128.

As seen in FIGS. 4 and 6 , the top or superior member 130 also includesan undersurface 132 with a relief area 134 that is adjacent to thecentral opening 102. The central opening 102 may be configured to permitthe surgeon to insert bone graft material into the inner cavity of theimplant 100 prior to implantation. The relief area 134 may besubstantially planar and the relief area 134 may be aligned with thehole 118 in the base member 110. The relief area 134 is relativelyrectangular with the long axis of the rectangle extending along thelongitudinal axis of the top member 130. The relief area 134 isconfigured to mate with a correspondingly shaped load head 170 of theexpansion mechanism 140 (see FIG. 8 ). The top member 130 may alsoinclude a hinge channel or pivot channel 136 for mating with the pivotcylinder 124 of the base member 110 to enable the implant 100 to extendon the proximal end while remaining closed on the distal end. The pivotcylinder 124 and hinge channel 136 allow the top member 130 to pivot orrotate around the outer diameter of the pivot cylinder 124 of the basemember 110 when expansion assembly 142 (see FIG. 8 ) is extended orretracted causing the top member 130 to tilt or slant relative to thebase member 110. In addition, the top member 130 may include an opening138 for mating with the alignment protrusion 126 of the base member 110.

Referring now to FIG. 4 with continued reference to FIGS. 5 and 6 , anexploded view of all of the components that comprise the implant 100 isshown. As shown in FIG. 8 , the expansion mechanism 140 of the implant100 includes an expansion assembly 142 and a drive rod 180. Theexpansion assembly 142 may include a cylindrical gear 150, a supportmeans 158, a threaded rod 160, and a load head 170. The verticalcylinder or cylindrical gear 150 (these names may be usedinterchangeably) may nest or be suspended within the hole 118 of thebase member 110. The cylindrical gear 150 may include externalsubstantially vertical depressions or circumferential serial depressions152 positioned on the outer surface of the gear 150 which extend aroundthe entire circumference. For example purposes, the gear 150 may have asmooth surface, above and below the substantially vertical depressions152. Positioning the circumferential serial depressions 152 around thecentral portion of the gear 150 may maximize strength and improvetrackability when the cylindrical gear 150 engages the drive rod 180.The circumferential serial depressions 152 may also include uniquelyoriented thread patterns. In addition, the gear 150 may include internalthreads 154 on the interior surface of the gear 150.

As shown in FIG. 7 , the support means 158 may sit on the shoulder 120(see FIG. 5 ) of the base member 110 and function to maintain theexpansion assembly 142 (see FIG. 8 ) in a vertical orientation relativeto the base member 110 and aligned with the hole 118. The support means158 may also be used adjacent to the gear 150 and threaded rod 160 andmay hold the gear 150 in the hole 118 (see FIG. 5 ). The support meansmay, for example, be in the form of a ring, snap ring, washer or othersimilar type of structure that will secure the expansion assembly 142(see FIG. 8 ) to the base member 110. The shoulder 120 may also operateas a bearing surface against which the support means 158 contacts tofacilitate the rotation of the expansion assembly 142 when actuated. Asshown in FIG. 5 , the notch 121 in the hole 118 of the base member 110may enable the support means 158 to be inserted into the shoulder 120.

As shown in FIGS. 4, 7 and 8 , the threaded rod 160 may include a pivotcylinder 162 located on the top or superior end of the threaded rod 160.The threaded rod 160 may also include external threads 164 extendingalong its length. The external threads 164 may be configured to matchthe internal threads 154 of the gear 150. The pivot cylinder 162 of thethreaded rod 160 may be inserted into a distal channel 172 of the loadhead 170. These constructs allow the load head 170 to pivot, slide, orrotate around the outer diameter of the pivot cylinder 162 when thethreaded rod 160 is extended causing the top member 130 to tilt orslant. A tilted or slanted load head 170 is shown in FIGS. 3 and 7 . Theload head 170 may also include a superior head surface 174. The superiorhead surface 174 may be shaped to match with the corresponding reliefarea 134 (see FIG. 6 ) on the undersurface 132 of the top member 130.The superior head surface 174 is configured to slide along the relief134 of the undersurface 132, if necessary, to allow for the expansionassembly 142 to lengthen to create the angled relationship of the topmember 130 relative to the base member 110. The relief 134 in theundersurface 132 and the correspondingly shaped load head 170facilitates the angulation process and the load transfer between the topmember 130 and the base member 110 while avoiding potential binding ofthe expansion assembly 142 during the expansion and retraction process.

The drive rod 180 of the expansion mechanism 140 (see FIG. 8 ) may beinserted into the adjustment opening 116 and sit in the channel 122 ofthe base member 110, as shown in FIGS. 4 and 7 . The drive rod 180 maybe comprised of a cylindrical shaft 182 with a worm gear 184 at one endof the cylindrical shaft 182. The cylindrical shaft 182 may also have anopening 186 at a second end of the cylindrical shaft 182 opposite theworm gear 184 for coupling with a tool 200. In addition, the cylindricalshaft 182 may include a channel 188 for mating with a pin 190 to securethe drive rod 180 in the base member 110 to enable adjustment of the topmember 130 without the drive rod 180 backing out of the implant 100. Thepin 190 may also prevent the drive rod 180 from backing out of theimplant 100 after implantation into the patient's spine. Byoff-centering the adjustment opening 116 and the channel 122 from thelongitudinal axis of the device 100, the worm gear 184 of the drive rod180, which is inserted into the channel 122, intersects with the hole118 of the base member 110. The worm gear 184 may be configured toengage with the gear 150 of the expansion assembly 142 which sits in thehole 118 of the base member 110. FIG. 7 shows the assembled implant 100without the top member 130 with the drive rod 180 positioned andextending through the length of the base member 110.

When the implant 100 is inserted into a patient using tool 200, as shownin FIG. 12 , the tool 200 engages the alignment channel 112, theattachment opening 114 and the adjustment opening 116, as described ingreater detail below. Once the tool 200 is inserted into the patientbetween two vertebrae, the drive rod 180 with the gear 150 function tomirror the rotational movement exerted by the tool 200, described ingreater detail below, and translate the movement to the gear 150. Theexpansion mechanism 140 functions to convert rotation movement of thegear 150 into linear or translational movement of the load head 170positioned at the superior end of the threaded rod 160. Rotation of thegear 150 will result in a travel distance of the threaded rod 160 whenthe expansion mechanism 140 is actuated by the tool 200. As the gear 150is coupled to the drive rod 180, the coupled gear 150 will turn as thedrive rod 180 is rotated, thus avoiding the need for the tool 200 topass through the entire length of the channel 122 to engage the gear 150on the far end of the implant 100.

With continued reference to FIGS. 1-8 , as the drive rod 180 is rotatedby the tool 200, the teeth 178 of the worm gear 184 positioned on theend of the drive rod 180 are configured to mate with the substantiallyvertical depressions 152 of the gear 150. As described above, theexpansion assembly 142 acts to convert rotational movement of the gear150 into translational movement of the threaded rod 160. This isachieved by allowing free rotational movement of the gear 150 whilerestricting the rotation of the threaded rod 160. By restricting therotation of the threaded rod 160, the rod translates in either an upwardor downward direction relative to the gear 150 depending upon whetherthe threads (external and internal) 154, 164 are oriented in aright-handed or left-handed direction. As discussed above, when thethreaded rod 160 moves, the load head 170 contacts the relief area 134of the undersurface 130 of the top member 130 to either move it awayfrom or towards the base member 110. In other words, the height of theimplant 100 either increases or decreases or the bone contacting surface104 will be angled relative to the base member 110 depending on therotational direction of the tool 200.

Referring now to FIGS. 9-11 , an alternative embodiment adjustableinterbody fusion device 100 including a locking mechanism 192 is shown.As shown in FIG. 11 , the locking mechanism 192 may include a shaft 194extending out from a head 196. The head 196 may include a plurality ofprotrusions 198 for engaging the lip 129 (see FIG. 10 ) in theadjustment opening 116 of the base member 110 to secure the lockingmechanism 192 in the base member 110. The head 196 may also include anopening 199 for engaging the insertion tool 200 or a similar tool. Theshaft 194 of the locking mechanism 192 may have a shape whichcorresponds to the shape of the tool opening 186 of the drive rod 180,for example, the shape may be a hexagon, square, or other multi-lobedconfiguration allowing the shaft 194 of the locking mechanism 192 to fitsecurely within the opening 186 of the drive rod 180. Similarly, thehead 196 may have a shape which corresponds to the shape of theadjustment opening 116, for example, the shape may be a circle, hexagon,square, or other multi-lobed configuration allowing the lockingmechanism 192 to securely fit within the adjustment opening 116 of thebase member 110 to secure the locking mechanism 192 in the implant 100to maintain a desired expansion or retraction. Other shapes for theshaft 194 and the head 196 of the locking mechanism 192 are alsocontemplated. The locking mechanism 192 may be, for example, made of arigid material or a deformable material. If the locking mechanism 192 ismade of a deformable material it may be made slightly larger than theopening 186 in the drive rod 180 and/or the adjustment opening 116 inthe base member 110, such that once it is inserted the larger size locksthe drive rod 180 in the desired position.

Referring now to FIGS. 12-19 , a tool 200 for inserting the implant 100into a patient is shown. The tool 200 and the implant 100 may form aninterbody fusion device system, as shown in FIG. 12 . The tool 200 isdesigned to engage the expansion mechanism 140 (see FIG. 8 ). Theinsertion end 202 of the tool 200 may be configured with a housing 204including a protrusion or alignment protrusion 206 shaped to correspondto the alignment channel 112 in the base member 110. The insertion end202 may also include an adjustment mechanism 208 and a securementmechanism 210 which protrude out of the distal end of the housing 204.The adjustment mechanism 208 may be configured, for example, to have ahex male head, square, or other multi-lobed configuration that willallow for the user to rotate the knob 224 of the tool 200 and cause theexpansion mechanism 140 to rotate. Opposite the insertion end 202, thetool 200 has a handle 212 which may be connected to the housing 204 ofthe insertion end 202 by a tube 214. The tube 214 may be coupled to thehousing 204 on the distal end and secured to the handle 212 at theproximal end by fasteners 248, for example, screws. The tube 214 mayhouse the securement mechanism 210 which may extend from the handle 212to the housing 204 inside the tube 214. In addition, the adjustmentmechanism 208 may also extend between the housing 204 at the insertionend 202 and the handle 212, relatively parallel to and outside the tube214.

As seen in FIGS. 15-18 , the handle 212 of the tool 200 may also includea first opening 216 and a second opening 218 along the longitudinal axisof the handle 212. In addition, the handle 212 of tool 200 may include athird opening 220 extending perpendicular to and engaging the first andsecond openings 216, 218. A fourth opening 222 may also be in the handle212 and may extend into the handle 212 from the proximal end of thehandle 212 into the third opening 220 and may run parallel with thefirst and second openings 216, 218. The handle 212 may also include aknob 224 which may be inserted into both the first and second openings216, 218 at a proximal end of the handle 212, an actuation bar 226 forinsertion into the third opening 220, and a spring plunger 228 forinsertion into the fourth opening 222. The knob 224 may include a head236 with a shaft 238 extending out away from the inferior surface of thehead 236. The shaft 238 of the knob 224 may also include a channel 240for mating with the actuation bar 226 to secure the knob 224 in theinserted opening 216, 218.

As seen in FIGS. 16 and 18 , the adjustment mechanism 208 may pass intothe first opening 216 from the distal end of the handle 212 enablingengagement with the distal end of the shaft 238 of the knob 224 wheninserted into the first opening 216 from the proximal end of the handle212. A tool engagement end 242 (see FIGS. 15-16 ) of the adjustmentmechanism 208 couples with the distal end of the shaft 238 to enablerotation of the adjustment mechanism 208. The securement mechanism 210may pass into the second opening 218 from the distal end of the handle212 enabling engagement with the distal end of the shaft 238 of the knob224 when inserted into the second opening 218 from the proximal end ofthe handle 212. In addition, the securement mechanism 210 may include aspring mechanism 246 inserted over the proximal end of the securementmechanism 210 to spring load the securement mechanism 210. A toolengagement end 244 of the securement mechanism 210 couples with thedistal end of the shaft 238 to enable rotation of the securementmechanism 210. The tool engagement ends 242, 244 may have, for example,a hex male head, square, or other multi-lobed configuration to enablerotation of the adjustment mechanism 208 or securement mechanism 210,respectively. The shaft 238 of the knob 224 when inserted into eitherthe first or second openings 216, 218 passes through a hole 230 in theactuation bar 226 before engaging the adjustment mechanism 208 orsecurement mechanism 210, respectively. The channel 240 in the shaft 238of the knob 224 engages the hole 230 in the actuation bar 226 to lockthe knob 224 in the first or second opening 216, 218.

During use a surgeon may insert the tool 200 into the implant 100 byaligning the protrusion 206 of the insertion end 202 of the tool 200with the alignment channel 112 of the implant 100. Once the tool 200 andimplant 100 are aligned and the actuation bar 226 is in an unlockedposition the shaft 238 of the knob 224 may be inserted into the secondopening 218 and coupled to the tool engagement end 244 of the securementmechanism 210. After the shaft 238 has coupled to the tool engagementend 244 of the securement mechanism 210, the actuation bar 226 may bemoved to the first locked position, as shown in FIGS. 12, 15 and 16 ,and the actuation bar 226 engages the channel 240 in the shaft 238 ofthe knob 224, as shown in FIGS. 15, 16 and 19 . As the actuation bar 226is moved to lock the knob 224 into the second opening 218, the springplunger 228 in the fourth opening 222 may engage a first channel 232 ofthe actuation bar 226 to lock the knob 224 in place in the handle 212.The head 236 of the knob 224 of the tool 200 may then be rotated whichin turn will rotate the securement mechanism 210. As the knob 224rotates the securement mechanism 210, the distal end of the securementmechanism 210 engages the threads 108 of the attachment opening 114 ofthe implant 100. The securement mechanism 210 of the tool will couplewith the attachment opening 114 of the implant 100 to secure the implant100 to the tool 200 for insertion into a patient. In addition, as thesecurement mechanism 210 engages the attachment opening 114 of theimplant 100, the adjustment mechanism 208 of the tool will engage theopening 186 in the drive rod 180 of the implant 100.

Once the implant 100 is secured to the tool 200, the physician mayremove the knob 224 from the second opening 218 of the handle 212 bymoving the actuation bar 226 to the unlocked position. As the actuationbar 226 is moved from the first locked position, shown in FIGS. 12, 15and 16 , to the unlocked position the spring plunger 228 disengages thefirst channel 232. With the actuation bar 226 in an unlocked positionthe shaft 238 of the knob 224 may be inserted into the proximal end ofthe first opening 216 in the handle 212 to engage the tool engagementend 242 of the adjustment mechanism 208. Once the shaft 238 has coupledto the tool engagement end 242 of the adjustment mechanism 208, theactuation bar 226 may be moved to the second locked position, shown inFIGS. 17 and 18 . As the actuation bar 226 is moved to the second lockedposition, the spring plunger 228 may engage a second channel 234 of theactuation bar 226 to lock the knob 224 into the first opening 216 in thehandle 212. After the actuation bar 226 of the handle 212 is in thesecond locked position, the implant 100 may then be inserted into thedesired position in the patient. The physician may then rotate the head236 of the knob 224 which in turn will rotate the distal end of theadjustment mechanism 208. As the head 236 of the knob 224 is rotated,the adjustment mechanism 208, which is coupled to the opening 186 in thedrive rod 180, engages the expansion mechanism 140 and expands the farend of the implant 100 to angle the top member 130 relative to the basemember 110. The cogs or teeth 178 of the worm gear 184 on the end of thedrive rod 180 are sized to mate with the corresponding serialdepressions 152 of the gear 150 to facilitate rotation of the gear 150when the knob 224 of the tool 200 is turned. Once the desired expansionof the implant 100 is achieved, the tool 200 may then be removed fromthe patient.

In the alternative embodiment shown in FIGS. 9-11 , prior to removingthe tool 200, the locking mechanism 192 may be inserted into the implant100 to secure the top member 130 of the implant 100 in the desiredexpansion and/or retraction relative to the base member 110. The lockingmechanism 192 may be inserted into the opening 186 in the drive rod 180by first securing the insertion tool 200 or a similar tool to theopening 199 of the locking mechanism 192. As the locking mechanism 192is inserted into the base member 110 and the drive rod 180, the shaft194 of the locking mechanism 192 fits securely within the opening 186 ofthe drive rod 180. In addition, the plurality of protrusions 198 on thehead 196 may engage the lip 129 in the adjustment opening 116 of thebase member 110. In addition, the drive rod 180 may be recessed withinthe base member 110 to provide a cavity for insertion of the lockingmechanism 192 into the base member 110, such that when the lockingmechanism 192 is inserted into the base member 110 of the implant 100 itis flush with the exterior surface of the base member 110.

The tool 200 may be removed from the patient by removing the knob 224from the first opening 216 of the handle 212. The knob 224 may beremoved from the first opening 216 by moving the actuation bar 226 tothe unlocked position to disengage the actuation bar 226 from the knobchannel 240 and the spring plunger 228 from the first channel 232 in theactuation bar 226. Once the actuation bar 226 is in an unlocked positionthe shaft 238 of the knob 224 may be removed from the first opening 216and inserted into the second opening 218 to engage the securementmechanism 210. After inserting the shaft 238 of the knob 224 in thesecond opening 218, the actuation bar 226 may be moved to the firstlocked position, as shown in FIGS. 15 and 16 to secure the knob shaft238 in the second opening 218 of the handle 212. In the first lockedposition, the spring plunger 228 may again engage the first channel 232to secure the knob 224 in the handle 212. The head 236 of the knob 224may then be rotated to remove the distal end of the securement mechanism210 from the attachment opening 114. As the securement mechanism 210rotates it disengages the threads 108 of the attachment opening 114 andthe protrusion 206 and adjustment mechanism 208 of the insertion end 202of the tool 200 slide out of the alignment channel 112 and adjustmentopening 116, respectively. It is also contemplated that the above methodfor inserting the implant 100 using tool 200 may be performed inalternative orders.

Referring now to FIGS. 20-28 , an alternative embodiment tool 300 forinserting the implant 100 into a patient is shown. The tool 300 and theimplant 100 may form an interbody fusion device system as shown in FIG.20 . The tool 300 is designed to engage the expansion mechanism 140 (seeFIG. 8 ). The insertion end 302 of the tool 300 may be configured with ahousing 304 including a protrusion 306 shaped to correspond to thealignment channel 112 in the base member 110. The insertion end 302 mayalso include an opening 308 for adjustment mechanism 342 or lockingmechanism inserter 344 and a securement mechanism 310 which protrude outof the distal end of the housing 304. The adjustment mechanism 342 maybe configured, for example, to have a hex male head, square, or othermulti-lobed configuration that will allow for the user to rotate theknob 324 of the tool 300 and cause the expansion mechanism 140 torotate. Opposite the insertion end 302, the tool 300 has a handle 312which may be connected to the housing 304 of the insertion end 302 by atube 314. The tube 314 may be coupled to the housing 304 on the distalend and secured to the handle 312 at the proximal end. The tube 314 mayhouse the securement mechanism 310 which may extend from the handle 312to the housing 304 inside the tube 314. In addition, a second tube 315may extend between the housing 304 at the insertion end 302 and thehandle 312, relatively parallel to and outside the tube 314, to housethe adjustment mechanism 342 or locking mechanism inserter 344.

As seen in FIGS. 21-23 , the handle 312 of the tool 300 may also includea first opening 316 along the longitudinal axis of the handle 312. Thehandle 312 may also include a second opening 318 which may extend intothe handle 312 from the proximal end of the handle 312 and run parallelwith the first opening 316. In addition, the handle 312 of tool 300 mayinclude a third opening 320 extending perpendicular to and engaging thefirst opening 316. The handle 312 may also include a knob 324 forattachment to a shaft 336, 338 of the adjustment mechanism 342 orlocking mechanism inserter 344, respectively, which may be inserted intothe first opening 316 at a proximal end of the handle 312, a gear shaft328 for insertion into the second opening 318, and an actuation bar 326for insertion into the third opening 320. The knob 324 may be attachedto a shaft 336, 338 of the adjustment mechanism 342 or locking mechanism344, respectively, and the shaft 336, 338 may extend out away from theinferior surface of the knob 324 when inserted. The shafts 336, 338 ofthe adjustment mechanism 342 or locking mechanism inserter 344 may alsoinclude a channel 340 for mating with the actuation bar 326 to securethe adjustment mechanism 342 or locking mechanism inserter 344 in theopening 316. The shafts 336, 338 of the adjustment mechanism 342 orlocking mechanism inserter 344 when inserted into the first openings 316pass through a hole 330 in the actuation bar 326. The channel 340 in theshafts 336, 338 of the adjustment mechanism 342 or locking mechanisminserter 344 engage the hole 330 in the actuation bar 326 to lock theadjustment mechanism 342 or locking mechanism inserter 344 in the firstopening 316. The handle 312 may further include a fourth opening 322 inthe distal end of the handle 312. The fourth opening 322 may allow theadjustment mechanism 342 or locking mechanism inserter 344 to pass outof the handle at the insertion end 302 of the tool 300. In addition, thefourth opening 322 may allow for the securement mechanism 310 to beattached to the distal end of the handle 312.

As shown in FIGS. 21-23 , the handle 312 may also include anintermediate housing 348 that mates with the fourth opening 322 tosecure the securement mechanism to the handle 312. A spring mechanism346 may be inserted into the fourth opening 322 of the handle 312 tohold a first gear 350 inside of a second knob 352. The first gear 350mates with the end of the securement mechanism 310 to enable rotation ofthe securement mechanism 310 by rotating the second knob 352 which inturn rotates the first gear 350 and the coupled securement mechanism310. The rotation of the second knob 352 allows a physician to rotatethe engagement end of the securement mechanism 310 to attach the implant100 to the tool 300.

The proximal end of the handle 312 may also include a second gear 354that sits in the first opening 316 and a third gear 356 that sits in thesecond opening 318, as shown in FIGS. 22 and 23 . The first opening 318may engage the second opening 318 to enable the gear teeth on the secondand third gears 354, 356 to overlap such that rotation of the secondgear 354 causes rotation of the third gear 356 and alternatively, suchthat rotation of the third gear 356 causes rotation of the second gear354. The second opening 318 may also include a longitudinal openingenabling the gear teeth of the second gear 356 to engage the interiorsurface of the third knob 358, which engages the proximal end of thehandle 312. The handle 312 may further include an end member 360 formating with the third knob 358. The end member 360 may be secured to thethird knob 358 using fasteners, not shown, such as screws. A gear shaft328 may be inserted into handle 312 through an opening 362 in the endmember 360 to engage a passage through the third gear 356.

As seen in FIGS. 21-24 , the adjustment mechanism 342 may pass into thefirst opening 316 from the proximal end of the handle 312, through thehandle 312 and the second tube 315 and extend out of the opening 308 inthe housing 304 enabling engagement with the implant 100. The proximalend of the adjustment mechanism 342 may extend through a passage in thesecond gear 354 and into the knob 324. The adjustment mechanism 342 maybe coupled to the second gear 354 and the knob 324 enabling rotation ofthe proximal end of the adjustment mechanism 342 by the knob 324 and thethird knob 358. The adjustment mechanism 352 may also pass through anintermediate housing 348 as it passes through the fourth opening 322 inthe distal end of the handle 312 and into the second tube 315. When theadjustment mechanism 342 is in place within the tool 300, the adjustmentend 364 extends out of the opening 308 in the housing 304 to enableengagement with the adjustment opening 116 in the implant 100. As shownin FIG. 24 , the adjustment end 364 may have, for example, a hex malehead, square, or other multi-lobed configuration to enable rotation ofthe drive rod 180 with a correspondingly shaped engagement end. Once theimplant 100 is in a desired expansion or retraction, the physician mayremove the adjustment mechanism 342 and insert the locking mechanisminserter 344 to lock the implant 100 in the desired expansion orretraction. The locking mechanism inserter 344, shown in FIGS. 25 and 26, may include an engagement end 366 with a shape corresponding to theopening 199 in the locking mechanism 192. The engagement end 366 of thetool 300 may be inserted into the opening 199 in the locking mechanism192 for insertion of the locking mechanism 192 into the implant 100.During surgery, the locking mechanism inserter 344 with the lockingmechanism 192 attached to the engagement end 366 will be inserted intotool 300 through the opening 316 in the handle 312, through theintermediate housing 348, through the second tube 315, and out of theopening 308 in the housing 304 of the tool 300 to engage the implant100.

As shown in FIGS. 27 and 28 , the locking mechanism 192 may be insertedinto the base member 110 and drive rod 180 using the locking mechanisminserter 344 (see FIG. 25-26 ) of the tool 300 to secure the implant 100in the desired expansion or retraction. The drive rod 180 may berecessed within the adjustment opening 116 in the base member 110 of theimplant 100 when the locking mechanism 192 is used. The tool 300 may beused in place of the tool 200 in the above surgical method to insert theimplant 100 into a patient. If tool 300 was used in the above describedmethod, the method may also include the steps of removing the adjustmentmechanism 342 after expansion or retraction and inserting the lockingmechanism inserter 344 to lock the implant 100 in the desired expansionor retraction using the locking mechanism 192.

As shown in FIG. 34 and described in greater detail above, the methodmay include obtaining a medical device 500, inserting and coupling atool to the medical device 510, slidingly inserting the medical deviceinto a space between two vertebral bodies 520, rotating a knob of thetool to move a first end of a top member in a vertical directionrelative to a body member 530, and removing the tool from the medicaldevice 540.

Another adjustable interbody fusion device 400 is shown in FIGS. 29-33 .The device 400, as seen in FIGS. 29-30 , may include at least onemoveable top or superior member 430 and a base or bottom member 410. Thetop member 430 may be detachably coupled to the base member 410. Thebase member 410 and top member 430 may have at least one through hole orcentral opening 102. The base member 410 may include a bone contactingsurface 104 and the top member 430 may also include a bone contactingsurface 104. The at least one through hole or central opening 102 andthe bone contacting surface 104 may be of the types described in greaterdetail above with reference to device 100.

As shown in FIGS. 29, 31 and 32 , the base member 410 may include a toolalignment channel 112, a tool attachment opening 114, and an adjustmentopening 116, as described above in greater detail with reference todevice 100. The base member 410 may also include a hole or lumen 118configured to receive the expansion mechanism 140 (see FIG. 8 ), asdescribed in greater detail above with reference to device 100. The basemember 410 may further include an internal circumferential shoulder 120,a notch 121, a channel 122, and an opening 128, as described in greaterdetail above with reference to device 100. The base member 410 may alsoinclude at least two pivot cylinders 412 each with at least one opening414 and at least one hinge channel 416.

The top or superior member 430 is shown in greater detail in FIG. 33 andmay include an undersurface 132 with a relief area 134 as describedabove in greater detail with respect to device 100. The top member 430may also include at least two hinge channels 432 and at least one pivotcylinder 434 with at least one opening 436. The at least two hingechannels 432 of the top member 430 may be configured to mate with the atleast two pivot cylinders 412 of the base member 410 (see FIG. 32 ).Likewise, the at least one pivot cylinder 434 may be configured to matewith the at least one hinge channel 416 of the base member 410 (see FIG.32 ). The openings 414, 436 are configured to align and receive a pin420 when the top member 430 is placed on the base member 410 to enablethe implant 400 to pivot on one end such that the implant 400 extends ona first end while remaining closed on a second end. The pivot cylinders412, 434, hinge channels 416, 432, and pin 420 allow the top member 430to pivot or rotate around the outer diameters of the pivot cylinders412, 434 when the expansion assembly 142 (see FIG. 8 ) is extended orretracted causing the top member 430 to tilt or slant relative to thebase member 410.

An exploded view of the implant 400 is shown in FIG. 31 . The implant400 includes the expansion mechanism 140 as shown in FIG. 8 . Asdescribed in greater detail above with reference to device 100, theexpansion mechanism 140 may include an expansion assembly 142 and adrive rod 180. The expansion assembly 142 may include the cylindricalgear 150, the support means 158, the threaded rod 160, and the load head170 as described above with reference to device 100.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has”, and “having”), “include” (and any formof include, such as “includes” and “including”), and “contain” (and anyform of contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises,” “has,”“includes,” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of a method or anelement of a device that “comprises,” “has,” “includes,” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

Although the example embodiments have been depicted and described indetail herein, it will be apparent to those skilled in the relevant artthat various modifications, additions and substitutions can be madewithout departing from its essence and therefore these are to beconsidered to be within the scope of the following claims.

What is claimed:
 1. An expansion mechanism for moving a first memberrelative to a second member, the expansion mechanism comprising: acylindrical gear sized to rest within an opening, the opening positionedwithin the first member; a threaded rod having a pivot cylinder on afirst end, wherein the threaded rod comprises a plurality of externalthreads extending along the length of the threaded rod; a load headhaving a top surface and a bottom surface, wherein the load head isconfigured to couple and move relative to the threaded rod; and asupport member, the support member being sized to be partiallypositioned within the opening in the first member, and wherein thesupport member is at least one of a ring, a snap ring, a washer and ano-ring.
 2. The expansion mechanism of claim 1, wherein the top surfaceof the load head is planar and is configured to engage a relief areadisposed within the second member.
 3. The expansion mechanism of claim2, wherein the bottom surface of the load head comprises a distalchannel configured to moveably engage the pivot cylinder of the threadedrod.
 4. The expansion mechanism of claim 1, wherein the support memberis positioned adjacent to the cylindrical gear.
 5. The expansionmechanism of claim 1, wherein the cylindrical gear further comprises aplurality of serial depressions disposed on an outer surface of thecylindrical gear.
 6. The expansion mechanism of claim 5, wherein theplurality of serial depressions extend around the circumference of thecylindrical gear and are oriented in a vertical direction.
 7. Theexpansion mechanism of claim 5, wherein the plurality of serialdepressions have a length that is less than the length of thecylindrical gear.
 8. The expansion mechanism of claim 5, wherein theouter surface further comprises a first circumferential smooth surfaceand a second circumferential smooth surface.
 9. The expansion mechanismof claim 8, wherein the plurality of serial depressions are positionedintermediate the first circumferential smooth surface and the secondcircumferential smooth surface.
 10. The expansion mechanism of claim 1,wherein the cylindrical gear further comprises an internal central boreopening extending from a first end to a second end of the cylindricalgear, wherein the internal central bore opening is threaded.
 11. Theexpansion mechanism of claim 10, wherein the threads of the internalcentral bore opening of the cylindrical gear mate with the plurality ofexternal threads of the threaded rod when the expansion mechanism isassembled.
 12. The expansion mechanism of claim 11, wherein the threadsof the internal central bore opening of the cylindrical gear areright-handed threads and the plurality of external threads of thethreaded rod are left-handed threads.
 13. The expansion mechanism ofclaim 11, wherein the threads of the internal central bore opening ofthe cylindrical gear are left-handed threads and the plurality ofexternal threads of the threaded rod are right-handed threads.
 14. Theexpansion mechanism of claim 1, further comprising a drive rod, whereinthe drive rod is configured for insertion into an adjustment opening ofthe first member to engage the cylindrical gear.
 15. The expansionmechanism of claim 14, wherein the drive rod comprises: a cylindricalshaft with a first end and a second end; a worm gear at the first end; atool opening at the second end; and a channel in the cylindrical shaftpositioned between the first end and the second end.
 16. The expansionmechanism of claim 15, wherein the channel is circumferentiallypositioned around the cylindrical shaft.
 17. The expansion mechanism ofclaim 15, wherein the worm gear is sized to mate with a plurality ofserial depressions disposed on an outer surface of the cylindrical gear.18. The expansion mechanism of claim 15, further comprising a pin,wherein the pin is fixed to an inner surface of the first member,wherein the pin is sized to articulate with the channel of thecylindrical shaft to maintain the position of the cylindrical shaft ofthe drive rod within the first member when rotated during the operationof the expansion mechanism.
 19. An expansion mechanism for moving afirst member relative to a second member, the expansion mechanismcomprising: a cylindrical gear sized to rest within an opening, theopening positioned within the first member; a threaded rod having apivot cylinder on a first end, wherein the threaded rod comprises aplurality of external threads extending along the length of the threadedrod; a load head having a top surface and a bottom surface, wherein theload head is configured to couple and move relative to the threaded rod;a drive rod, wherein the drive rod is configured for insertion into anadjustment opening of the first member to engage the cylindrical gear,wherein the drive rod comprises: a cylindrical shaft with a first endand a second end; worm gear at the first end; a tool opening at thesecond end; and a channel in the cylindrical shaft positioned betweenthe first end and the second end; and a locking mechanism, wherein thelocking mechanism is configured to engage an adjustment opening in thefirst member and the tool opening in the drive rod, the lockingmechanism comprising: a head including an opening for engaging aninsertion tool and a plurality of protrusions configured to engage theadjustment opening; and a shaft extending away from the head andconfigured to engage the tool opening in the drive rod.
 20. A method ofusing an interbody fusion device, comprising: obtaining an interbodyfusion device, wherein the interbody fusion devices comprises a basemember comprising a first end, a second end, a first bone contactingsurface, a first inner surface opposite the first bone contactingsurface, and at least one projection extending from the first innersurface along a first end portion of the base member forming a pivotcylinder, wherein the pivot cylinder is fixed to the first innersurface; a top member comprising a first end, a second end, a secondbone contacting surface, and a second inner surface opposite the secondbone contacting surface including a hinge channel extending along afirst end portion of the top member, wherein the pivot cylinder isconfigured to engage the hinge channel to enable the hinge channel topivot on and about the pivot cylinder; and an expansion mechanism formoving the top member relative to the base member to cause the topmember to pivot relative to the base member on and about the pivotcylinder making an incision to expose a first vertebral body and asecond vertebral body of a patient's spine; preparing a space betweenthe first vertebral body and the second vertebral body for receiving theinterbody fusion device; obtaining an insertion tool, the insertion toolcomprising: a handle; an insertion end; at least one tube extending awayfrom the handle and connecting the handle and the insertion end; a firstknob configured to couple to the handle; and an actuation bar moveablebetween a first position and a second position to enable the first knobto engage an adjustment mechanism in the first position and a securementmechanism in the second position; inserting the insertion tool into anopening in the base member and coupling the insertion tool to theinterbody fusion device; inserting the interbody fusion device into thespace between the first vertebral body and the second vertebral body;rotating the insertion tool to move the top member relative to the basemember: uncoupling the insertion tool from the interbody fusion device;and closing the incision.